There is a great deal of art depicting the various approaches to regulating the air flow and/or amount of fuel metered through a carburetor to an internal combustion engine. The reason for such control is that the air/fuel mixture is improved by control, as compared to a fixed schedule of air/fuel mixture, because engine operating conditions change, air density changes (as a function of temperature, barometric pressure and altitude), and the fuel composition changes. The better the regulaton of the air/fuel ratio, the more efficient the engine operation and the more economical is the cost of operation. The engine can be run on a leaner mixture if it is precisely and quickly regulated. However most of the systems previously developed are unduly complex, and thus expensive, in construction and operation. The more complicated the circuitry and transducer arrangements, the more potential there is for a shortened mean time between component failure, with consequent expense and unavailability of the vehicle during repair.
It is therefore a primary object of the present invention to provide a system for regulating the air/fuel ratio delivered to an internal combustion engine which is simpler and more efficient than earlier known systems.
A related object of the invention is to provide such a system which accommodates a change in system operation in accordance with the operating speed of the engine.
Yet another important object of the invention is to provide such an arrangement in which the control system is modified in its operation during vehicle start-up to ensure a rich mixture is available at that time.